"icers, officers or employees of the United States duly authorized to carry such weapons, banking institutions, public carriers who are engaged in the business of transporting mail, money, securities, or other valuables, wholesale dealers and retail dealers licensed under section 10 of this Act.D.C.Code Sec. 22-3214, 47 Stat. 654 (emphasis added).From a mere reading of this section it is obvious th" . . . .